1. Field of the Invention
The present invention relates in general to a communication apparatus including a line interface portion which receives and transmits data from and to a line and which includes a data access arrangement device in which is incorporated a detection circuit capable of detecting at least one of a line voltage and a line current.
2. Discussion of Related Art
As a communication apparatus, there is conventionally known a telephone set which reproduces, by a telephone receiver thereof, a voice signal transmitted from public switched telephone network (PSTN) via a telephone line. This kind of telephone set suffers from, due to transmission loss, variation in an input level of the voice signal inputted into the telephone receiver depending upon the length of the telephone line connected to an exchanger. Therefore, in the telephone set connected to the telephone line which is relatively long, the reproduction volume of the voice to be reproduced by the telephone receiver is small, so that a user may feel difficulty in hearing the voice during conversation with a communication partner.
To solve the problem indicated above, there is conventionally proposed a technique as disclosed in JP-A-5-347661, for instance. In the disclosed technique, a detection circuit capable of detecting a line current is disposed at a position that is nearer to a line than a line interface portion which transmits a dial signal and which performs control relating to status of closing and connection of the line, and an amplification factor of an amplifier provided on a telephone receiver is adjusted on the basis of a detected value of the detection circuit.